Nature News

http://www.nature.com/news/2011/110517/full/news.2011.297.html

Elie Gardner

Officials in Chile have approved a controversial US$3.2-billion project to construct five hydropower dams in Patagonia.

The HidroAysén project — a collaboration between the country's two biggest energy firms — plans to generate 2,750 megawatts of power by damming two major rivers, the Baker and the Pascua. But it must first seek approval for a 2,300-kilometre transmission line, costing another US$3.8 billion, that would carry power to Santiago.

The project was finally given the go-ahead after an arduous three years in the approval process. The Environmental Impact Assessment was first presented to the Environmental Assessment Commission of Coyhaique — a regional government body in southern Chile — in August 2008, but the commission wasn't satisfied with it and asked for an addendum.

Dozens of public organizations and thousands of individuals pointed out weaknesses in the study, saying that it lacked crucial information, ignored important issues, used incomplete data, misrepresented facts and contained poor analyses. The project had to submit the assessment three more times, responding to 4,046 comments, before it was finally approved.

Daniel Fernández, executive vice-president of HidroAysén, calls the study the "most extensive and comprehensive environmental assessment in the history of Chile".

No improvement

But those who criticized the original work say that many of their complaints still stand.

Claudio Meier, an engineer at Chile's University of Concepción who has been reviewing environmental-impact assessments for hydropower projects in the country for the past 20 years, was hired by Chile's water authority to review the original document. He says that the assessment was "built around anecdotal data" – for example, the studies on sediment were based on predictions and not actual measurements. What it lacked, in his opinion, was an understanding of ecosystem functions. For instance, the document reported impacts on water temperature, clarity and sedimentation, but did not address how these changes would affect the ecology of the rivers.

Peter Goodwin, founder of the Center for Ecohydraulics Research at the University of Idaho in Boise, says that rigorous scientific methods were not employed and the studies were not conducted over a long enough period to capture environmental variability, a problem made worse by the lack of pre-existing information on the pristine and remote Patagonian ecosystems.

"A baseline is important so you can detect in the future what the difference from normal is," Goodwin said. "Without a solid baseline study, you don't know what you are losing."

Orlando San Martin, an environmental adviser at Sweco, one of the consultancy firms commissioned to conduct the environmental assessment, says that his company, headquartered in Stockhom, did perform some extra baseline studies, but the project proposal and mitigation measures haven't changed much in the revision process. "The three revisions have allowed us to complement studies and reinforce mitigation measures in line with suggestions and requirements from the different governmental services participating in the environmental evaluation system," says San Martin.

Minimum requirements

Roberto Román, an engineer at the University of Chile in Santiago and vice-president of membership affairs at the International Solar Energy Society in San José de Maipo, says that the assessment shows that the project complies with Chilean law "at the lowest level that society is willing to accept".

But many say that the law needs to be made tougher. Román says that it should require a comparison to alternative projects, as is common in the United States and Europe. Meier, however, says that the assessment studied only the impact of the dam construction and not the impact of the transmission line. Because the line requires separate approval, they did not need be considered together.

Such renewable-energy projects have strong political support in Chile. The country imports 75% of its energy in the form of oil, gas and coal, and, according to statistics from the National Energy Commission, must double its energy capacity in the next 10–12 years to meet demand — although Román disputes that figure.

But Chilean president Sebastián Piñera has said that the country needs a base of large, reliable power plants that use sources such as coal, hydro, or nuclear, arguing that renewable energy can't serve the country's needs cost-efficiently in the short term. HidroAysén says that Chile is using just 25% of its hydroelectric potential and promises to reduce the country's dependence on imported fuels.